Art of producing printing-surfaces for use in printing-presses.



SPENCER oAnLEToN, OF NEW YORK, n. Y;, AssiGNoR To 'rnri OF NEW YORK, Y., A ooRPoRa IoNoF .dKTIN EXGRAVING COMPANY,

NEW YORK.

ART or rrtonucme-rnmrmesmnons ion use m PRINTING-PRESSES.

Specification of Letters I Application filed December 16,1905. Serial in. 292,102.

Patented Aug. 6, 1907.

To all whom it may concern:

Be it known that I, SPENCER CARLETON, a citizen of the United States, and a resident of New York city, in the countyof New York and State of New York, have invented certain new and useful Improvements in the Art of- Producing Printing-Surfaces for Use in Printing-Presses, of which the following is a specification. i

producing printing surfaces for use in printing precses and the like.

The object accomplished by the invention is to produce, by an expeditious and comparatively inexpensive proces a very superior printing surface, the impres ions from which are more faithfully true to the original than those produced by methods at present in use.

While in no sense confining the invention to use in the production of half-tone printing plates, I will describe the same as applied to suchproduction, since thereby a clear understanding of the invention and its advantages may he had.

The methods at. present in use for producing halftone plates are well known and it is also well known that in the practice of such methods great expense is necessarily incurred due to fine hand-work required to be applied to the originals to the negatives and to the plates, prior to, during and after the etching, to reproduce the original as faithfully as may be.

The present methods of producing half-tone plates also usually involve the employment, in the camera, of a plate prepared by the collodion process. This, even when in the form of emulsion, is relatively insensitive, and therefore slower in operation, than the gelatin dry plate which I propose. Moreover, the wet collodion plate, whatever its exposure in the camera, fails to reproduce gradations of light and shade with delicacy approaching that of the dry plate.

A further disadvantage in existing processes in general lies in the use of a plate (metal, stone or glass) having upon, or applied to its surface a layer, or what we may throughout this specification designate a coating, comprising asphalt fats, waxes, silicates, gums, resins, sensitized glue, gelatin or the like, the use of some of which neces itates a baking step or burning in and in all cases the application of long and. delicate manual treatment of the plateprior to, during and after the etching. These steps consequent to the use of said coatings involve, not only time and cab pense, but also risk to final success. Itmay be added that the tendency of such coatings to receive impressions imperfectly constitutes a continual source of failure in existing methods. Fidelity to the original as well as quality and artistic merit of the engraving produced suffer therefrom. I may mention also one 4 The invention relates to improvements in the art of very objectionable feature of some etched plates as heretofore manufactured, is due (especially when the result is not prevented by the use of dragons blood or the like) to undercutting or undermining of the lines, dots, stipples or-grains of the image. In this way some of these lines or dots may be entirely eaten away and lost during the etching. In every instance they become roughened and uneven, thereby impairing the quality of the printing surface." When a dove-tail is formed by the undercutting, perfect electrot-ype copies of such plates can be made only with great diflicully. if at To avoid these and other objectionable-features, processes 'of to-day frequently have to resort to succesive partial etchin.that is after a short action of the etching medium it is neces ary to stop, wash and dry the plate, and cover the tops and sides of the lines or dots with a resinous powder. The plate has then to be heated to melt the powder, which thereby becomes impervious to the etching "media and protects the sides of the lines and dots from undercutting. But the heating must be done with greatest care lest the bottoms of the grooves between the lines or dots be filled and further etching be prevented. The partial etching step and the protecting step must be repeated in alternation until the plate is finally etched to the desired depth. All this is time consuming. troublesome and not always successful.

A property presented by half-tone plates produced by present processes is that the stipples or dots are imperfect in outline, appearing rounded or ilregular in section when intended to be square-shouldered. From this results a. loss of color as it is termed, that is, alos of line gradations. of light and shade, with less faithfulness'to the original. 4

The disadvantages enumerated are nearly if not en tirely eliminated by my process and many new and important qualities thereby gained for the final product. I will therefore concisrly describe a satisfactory method. of putting my process into practice. Equivalent orsubstitute methods or means will be mentioned further on. As previously stated I describe the process as applied to half-tone engraving for convenience in exposition only.

The first step in the practice of my invention as applied to half-tone engravings, is to photograph the original picture, drawing or other object, usually with the interposition of the customary or any suitable screen or equivalent means. The sensitive plate will by preference be the usual dry plate.

The second step of my process includesthe preparation of the plate upon which is to be printed, by the action of light, the image appearing on the negmtive.

I avoid the use of "coatings" upon, or applied to the plate, with their consequent manipulations and disadvantages. By the term "coating" as used in this 50. the plate.

specification we mean a substance or substances physically laid upon or applied to the surface of the plate but not an integral partof same. For this we substitute a substance or substances chemically united to and in- 5 corpomted with the surface of the plate, being so united or bound that the-combination becomes a new substance or material; this latter by such union thereby acquiring sensitiveness to light. I print directly upon a sensitized metal surface. By. sensitized I mean 1 0 rendered sensitive to the action of light. I first provide a metal plate, preferably of copper, of suitable dirnens sions and see that it is well cleaned,'smooth and polished. This metal plate or copper plate, as I may for convenience call it, is then silver plated by anyof the usual plating processes, and is then again thoroughly cleaned and polished preparatory to being sensitized and having the image printed thereon from the negative. A convenient way to sensitize the metallic surface is to expose said metallic surface, which in this ing stance is silver, face downwards to the vapor of iodin.

Solutions or compounds of iodin may be made to serve a similar purpose. The surface may be rendered more highly sensitive by subjecting it to the action of bromin (or its compounds) as well as to the iodin. This 2 also may conveniently be done with vapor of the sensitizer.

.The third step in the practice of my process is to impresstlze image upon the sensitized metal surface of the plate. This I usually do by printing through the half- 0 tone negative by means of light, to accomplish which I simply tightly apply the negative against the sensitized metal surface and expose the same to the action of light.

The fourth step in the practice of my process is the rendering of the image on the sensitized metal surface resistant to the action of the etching medium and also ing held face downward over the mercury. In'this use of mercury the latter performs two functions, to-wit: as

a developer and as afiresist to the action of the et;ch-,

ing medium. I find itconvenient, though notat gll essential, to fix the image on the plate by means of hyposulfite of soda or other suitable medium. By the fixing process the tendency of the'parts less acted upon by the light to resist the action of the etching medium is removed. I y I The fifth step in my process involves the etching of The etching medium attacks that portion of the surface unprotected by the resist. The ill. stance I am citing being the application of my process to half-tone engraving, the etching medium attacks "the surface between the dots created primarily by .the

screen in the camera, until finally the plate bears the image in the form of projecting dots or studs, the tops of these dotsor studs being coated thinly with Iner-v cury. may say that the picture on the plate, after the latter has been taken from the etching medium is a picture in mercury dots, portions of the plate between thcse dots, but not under them, having been eaten away. The etching intp the plate is then continued to the desired depth. The etching process may be expedited by the use of an electric current.

The fifth step in my process may also be expedited 6 5 and improved by using a varying electric current, or

by varying the direction of the current or by using an alternating current. Ordinarily after the etching has continued for a certain time, either with or without the current,- and before proper penetration or depth 'has been-attained, the process stops because of the formation on theplate of a substance which seems to resist the action of the etching. medium. It is at this point that I vary the direction of the current or if a.

current has not up to that time been used I apply the current in a direction reverse to the ordinary, making the plate the cathode, preferably with copper as an anode. The reverse current is continued for a short period and its effect is that the plate may be withdrawn from the bath and, after wiping, a feat which could not .be performed without completely ruining without hindrance. The wiping of the plate, as just hereinbefore referred to, is for the purpose of removing the plate except for the action of'the reverse current, the etching may be continued to a sufficient depth the .formed substance from the surface of the plate.

vBy this means the plate will be found to be very cleanly etched. The etching may be completed, that is, carried to the desired depth in the copper plate, with entirely satisfactory results in the electrolytic bath, with the plate as an anode, in the presence of the current. I find it, however, convenient to ob tain the .deeper etching by removing the plate from the action of the current as soon as the unprotected portions have been completely penetrated. I then immerse the plate in an ordinary etching bath until etched to the desired extent. s

A surface comprising an image formed in raised or relief dots, stipples, studs, grains, or the like, in which gradations of light and shade are represented by the relative size and proximity of these dots, stipples, studs, grains and the like, maybe called a disconnected printing surface. Reproductions therefrom may be made at will by the usual methods of printing.

The advantages of my invention are manifold, not onlyas to the, methods of producing half t one printing plates, but also as applied to the production of 'line, intaglio and other printing plates and engravings.

My process very greatly simplifies and cheapens the cost of producing printing plates and engravings and eliminates many 'of the steps which consume the greatest amount of time and labor. In the first place my process dispenses with most, if not all, of the hand work applied to the original, to the negative, and to the plate itself prior to, during and after the etching,

fectly practicable and highly desirable to use the dry.

plate, filmor equivalent in the camera; The disadvantages in loss of color and faithful reproduction of the original, resulting from the use of the slower and less sensitive collodion plate have been mentioned. One of the great advantages of my invention therefore resides in the fact that in practice the dry plate, film,

direct reproductions. For this purpose a portable of any convenient camera. in connection with dry plates,

. films or equivalent, and a screen or its equivalent,

. since in accordance with my invention and my awayofthedotsisirli for whatever the "screens o may be used with perfect success to copy directly original objects, such as landscapes, living and net uml objects, statuary and the like. Theadvantages of this short-cut are obvious. recopying or transfer between the original subject and the final printing plate results in low of color and detail. e v

I am Well aware that in this art the use of a dry plate has been tried to some extent. My invention renders the use of the dry plate, film or equivalent, not only a possibility, but gives superior results and is successful in regular practice.

Through the diBGlld of coatings upon or applied to plates I avoid many difficulties, such as all burning in, mechanical transfers and etching in successive partial steps. By my process the plate may be etched to completion in one operation. Y

It is obvious that with the use of the more sensitive dry plate and a highly sensitized metal surface the resultant product will be a far more faithful reproduction both in fcolor and in detail of the original subject.

I would call attention to the fact that it is through the increased sensitiveness and the retention, unharmed throughout the etchingof fine gradations of color and detail, secured in the sensitized metal plate, that the finer qualities of the dry plate negative may be made available in-regular practice. 7

N 0 special care is required in the etching of my plate expe rience the plate prepared as licreinoefore described is in no danger of being injuredin etching.

The mercury forms a perfect resist and the etching is always along the valleys between the dots, lines or the likei p 5 M In the plates manufactured in accordance irith my invention the lines, dots or stipples are not undercut or undermined by theetching medium, but have clean sharply defined edges, with side surfaces which incline outwardly and downwardly at each line, dot or stipple. The intervening spaces form regular valleys. which may he etched as deeply as desired without any danger whatever of undercutting." This is a feature of the utmost importance in this art.

A feature resulting from the practice of my process and the employment of asensitized metal surface is that the stipples, or dots are perfect in outline, appearing square-shouldered in section, in lieu of stipples or dots which areimperfect in outline, appearing rounded or irregular in section when intended to be squareshouldered, the trueness of the stipples or dots improving the colofrff; detail, often the artistic value oft-lie engraving and being imlicinible of hill attainment. in p v emplop'ng coatings upon the plates. The absence of rounding and eating the plates of my process equivalent I employed for disconnecting the It is well known that every Whilejlie dryplate or film will by preference be used the invention in its broader scope is not thereto. The disconnectionof the surface or formation of the "dotn o rstipples on the plate is due toth employment of a screen and Tune the term screen in a generic sense and mean thereby to include the scope of my proccs any and all of the several means and methods, either singly or in combination, which have been devised for producing the stipplc effect. The sensi tized metal surface, disconnected by the screen or any suitable means, may he placed in the camera and the image photographed directly thereon. For the purpose. of the subsequent steps in my process either a late'ntfor a .printed outand visible image upon the sensitized metal serves.

The. invention in its broader scope is not limited to the method or means referred to'for sensitizing the mecompounds may be used for this purpose and it being my intention not to confine the invention, in its broader scope, to any special metal surface nor to any special method or means for sensitizing said surface, except that in accordance with my invention I do sensitize a metal surface and omit the application of sensitive coatings and the like thereto." For example I find it quite practicable and at times most convenient to sensitize a metal such as copper directlymsingtherefor the bromid of copper. This plate may be exposed in the camera or have the image printed upon it while in either a wet or dry state. The development may be by mercury or by any of the usual developers of commerce or even by a diluteacid, the image built up by the de veloper acting as a resist in etching. 4

Ihave described hereinbefore the best method known to me for carrying my invention into effect for half-tone engravings and the method described will be found to be entirely satisfactory, but I do not confine my invention in its broader scope exclusively to half-tone engravings, nor to the use of a copper plate as a base. nor to the employment of a silver surface on a copper or other plate, nor to any special means or methods of producing the sensitized metal surface and rendering the image resistant to the etching medium, since I believe I am the first to produce a relief disconnected printing surface by means of a sensitized-metal surface for use in printing engravings, and also the first to impres by means of light. directly upon a sensitized-metal surface. employing a half-tone photographic plate, negative or positive, for the pm of engraving, and also the first to print an image upon a sensitized-metal plate, without the .aid of a camera, by the action of light paming through a transparent or translucent body said image; This process of directly a metal surface without the use of coatings may rmdily be applied to curved or uneven surfaces, or otherwiseas re quirements may suggest. Hence it is peculiarly adaptable for rollers, cylinders, and other like devices; for the contributory plates or mllers used for embosing; for lithography; for wall paper and fabric printing; for threecolor and other color printing processes. For curved surfaces, films, stripped or otherwise, are advantageous.

tallic surface, since other halogens or their solutions or i sensitizing method described, or a solution of bromin or t The sensitized metal surface may be used for the production of either intaglio, plane or relief surfaces; particularly for relief half-tone printing plates. It may be applied to metal, glass, stone, earthenware, pottery, porcelain, wood, and other surfaces. The use of the sensitized metal plate is equally serviceable for the reproductionof lines, full-tones and any and all of the urposes of the art, replacing with advantage transfer and other existing methods in use for these purposes. I desire also to say that, the negative produced by the camera. using the term negative in a popular sense, may be transferred to another transparent plate which may be called a positive, considered in a more technical sense. and the printing on the sensitized metal surface be performed through this positive 'of the image primarily produced by the camera, either plate, in the sense of this applit ation being considered as a half-tone negative.

I do not limit my invention exclusively to the production of half-tone plates nor otherwise than as may be indicated in the claims. i

' ing surface comprising the production of a sensitizedmetal surface, producing thereon by the action of light on image in dots or stipplcs. rendering the image resistant to the action of an etching medium by a material serving as. 'a developer and as a resist, and etching the plate.

1;. The method of producing a relief printing surface comprising the production of an image on a transparent or translucent body, producing a sensitized-metal surface,

soaacs applying said body directly to said surface and printing said image thereon by the action of light passing through said body, rendering the image resistant to the action of an etching medium, and etching such surface.

4. The method of producing a relief disconnected printin; surface crmprising the production of a half-tone pho tographic negative; producing a sensitized-metal surface. printing thereon by means of light the image of the nega tive. rendering the image resistant to the action of an etching medium. and etching such surface.

5. The method of producingan etched'surface comprising the production of a sensltized-metal surface, producing thereon by the action of light an image in dots or stipples. rendering the image resistant to the action of an etching medium. and etchingthe surface in a bath in the presence of an electric current.

6. The method of-producing an etched snrface-compris ing the production of a sensitized-metal surface, producing thereon by the action of light an image in dots or stipples. rendering the image resistant. to the action of an etching medium. etching the surface. for a certainperiod. in a bath in the presence of an electric current, reversing the electric current for a certain period, the plate then be ing the cathode. removing the formed substance from the surface of the plate. and continuing the etching to the proper depth.

' T. The method of producing an etched surface comprising the sensitizing of a metal surface, producing thereon by the action of light an image, rendering the image resistant to the action of an etching medium, etchingthe surface in a bath for a certain period, applying a current of electricity to the bath with the plate as a cathode, re-

moving the formed substance from the surface of the plate, and continuing the etching to the proper depth.

Signed at New York cit-y, in the county of New York and State of New York this 14th day of December A. D. 1905. s i c SPENCER CARLETON.

'itnessesi CHAS. CfGrr L, An'rnur: MARION. 

